Tissue closure system

ABSTRACT

Tissue closure systems are described herein. Such a system may include a deployment catheter and an attached imaging hood deployable into an expanded configuration. In use, the imaging hood is placed against or adjacent to a region of tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid, such as saline, can be pumped into the imaging hood until the fluid displaces any blood, thereby leaving a clear region of tissue to be imaged via an imaging element in the deployment catheter. Additionally, the system can be deployed in a number of various ways to effect the closure of wounds or openings in the patient body.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. Prov. Pat. App.Ser. No. 60/737,521 filed Nov. 16, 2005 and is a continuation-in-part ofU.S. patent application Ser. No. 11/259,498 filed Oct. 25, 2005, whichclaims priority to U.S. Prov. Pat. App. Ser. No. 60/649,246 filed Feb.2, 2005, each of which is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates generally to medical devices used forvisualizing and/or closing openings or defects within a body. Moreparticularly, the present invention relates to apparatus and methods forvisualizing and/or closing openings or wounds, e.g., septal defects,patent foramen ovale (PFO), etc., within a patient's body such as withinthe heart, which are generally difficult to image because of surroundingopaque bodily fluids such as blood.

BACKGROUND OF THE INVENTION

Conventional devices for visualizing interior regions of a body lumenare known. For example, ultrasound devices have been used to produceimages from within a body in vivo. Ultrasound has been used both withand without contrast agents, which typically enhance ultrasound-derivedimages.

Other conventional methods have utilized catheters or probes havingposition sensors deployed within the body lumen, such as the interior ofa cardiac chamber. These types of positional sensors are typically usedto determine the movement of a cardiac tissue surface or the electricalactivity within the cardiac tissue. When a sufficient number of pointshave been sampled by the sensors, a “map” of the cardiac tissue may begenerated.

Another conventional device utilizes an inflatable balloon which istypically introduced intravascularly in a deflated state and theninflated against the tissue region to be examined. Imaging is typicallyaccomplished by an optical fiber or other apparatus such as electronicchips for viewing the tissue through the membrane(s) of the inflatedballoon. Moreover, the balloon must generally be inflated for imaging.Other conventional balloons utilize a cavity or depression formed at adistal end of the inflated balloon. This cavity or depression is pressedagainst the tissue to be examined and is flushed with a clear fluid toprovide a clear pathway through the blood.

However, such imaging balloons have many inherent disadvantages. Forinstance, such balloons generally require that the balloon be inflatedto a relatively large size which may undesirably displace surroundingtissue and interfere with fine positioning of the imaging system againstthe tissue. Moreover, the working area created by such inflatableballoons are generally cramped and limited in size. Furthermore,inflated balloons may be susceptible to pressure changes in thesurrounding fluid. For example, if the environment surrounding theinflated balloon undergoes pressure changes, e.g., during systolic anddiastolic pressure cycles in a beating heart, the constant pressurechange may affect the inflated balloon volume and its positioning toproduce unsteady or undesirable conditions for optimal tissue imaging.

Accordingly, these types of imaging modalities are generally unable toprovide desirable images useful for sufficient diagnosis and therapy ofthe endoluminal structure, due in part to factors such as dynamic forcesgenerated by the natural movement of the heart. Moreover, anatomicstructures within the body can occlude or obstruct the image acquisitionprocess. Also, the presence and movement of opaque bodily fluids such asblood generally make in vivo imaging of tissue regions within the heartdifficult.

Other external imaging modalities are also conventionally utilized. Forexample, computed tomography (CT) and magnetic resonance imaging (MRI)are typical modalities which are widely used to obtain images of bodylumens such as the interior chambers of the heart. However, such imagingmodalities fail to provide real-time imaging for intra-operativetherapeutic procedures. Fluoroscopic imaging, for instance, is widelyused to identify anatomic landmarks within the heart and other regionsof the body. However, fluoroscopy fails to provide an accurate image ofthe tissue quality or surface and also fails to provide forinstrumentation for performing tissue manipulation or other therapeuticprocedures upon the visualized tissue regions. In addition, fluoroscopyprovides a shadow of the intervening tissue onto a plate or sensor whenit may be desirable to view the intraluminal surface of the tissue todiagnose pathologies or to perform some form of therapy on it.

Thus, a tissue imaging system which is able to provide real-time in vivoimages of tissue regions within body lumens such as the heart throughopaque media such as blood and which also provide instruments fortherapeutic procedures upon the visualized tissue are desirable.

BRIEF SUMMARY OF THE INVENTION

A tissue imaging and manipulation apparatus that may be utilized forprocedures within a body lumen, such as the heart, in whichvisualization of the surrounding tissue is made difficult, if notimpossible, by medium contained within the lumen such as blood, isdescribed below. Generally, such a tissue imaging and manipulationapparatus comprises an optional delivery catheter or sheath throughwhich a deployment catheter and imaging hood may be advanced forplacement against or adjacent to the tissue to be imaged.

The deployment catheter may define a fluid delivery lumen therethroughas well as an imaging lumen within which an optical imaging fiber orassembly may be disposed for imaging tissue. When deployed, the imaginghood may be expanded into any number of shapes, e.g., cylindrical,conical as shown, semi-spherical, etc., provided that an open area orfield is defined by the imaging hood. The open area is the area withinwhich the tissue region of interest may be imaged. The imaging hood mayalso define an atraumatic contact lip or edge for placement or abutmentagainst the tissue region of interest. Moreover, the distal end of thedeployment catheter or separate manipulatable catheters may bearticulated through various controlling mechanisms such as push-pullwires manually or via computer control

The deployment catheter may also be stabilized relative to the tissuesurface through various methods. For instance, inflatable stabilizingballoons positioned along a length of the catheter may be utilized, ortissue engagement anchors may be passed through or along the deploymentcatheter for temporary engagement of the underlying tissue.

In operation, after the imaging hood has been deployed, fluid may bepumped at a positive pressure through the fluid delivery lumen until thefluid fills the open area completely and displaces any blood from withinthe open area. The fluid may comprise any biocompatible fluid, e.g.,saline, water, plasma, Fluorinert™, etc., which is sufficientlytransparent to allow for relatively undistorted visualization throughthe fluid. The fluid may be pumped continuously or intermittently toallow for image capture by an optional processor which may be incommunication with the assembly.

The imaging hood may be formed into any number of configurations and theimaging assembly may also be utilized with any number of therapeutictools which may be deployed through the deployment catheter.

Moreover, the imaging assembly may be utilized to deploy one or moreanchors into or through tissue regions for effecting the closure ofopenings or wounds such as atrial-septal defects or PFO. Closure may beeffected via a number of different mechanisms and procedures. In onevariation, once the imaging hood has been desirably positioned proximateto the defect or PFO and visualized directly, a cannula or piercingneedle may be advanced through the deployment catheter and through theimaging hood. One or more tissue anchors may then be deployed eitherthrough the cannula or needle to approximate and secure the tissueopening. Alternatively, a patching mechanism may be utilized forsecurement over the opening via barbs, projections, etc., or via anynumber of expandable securement devices which may be passed through theopening and expanded on a distal side of the opening to urge the patchagainst the tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a side view of one variation of a tissue imaging apparatusduring deployment from a sheath or delivery catheter.

FIG. 1B shows the deployed tissue imaging apparatus of FIG. 1A having anoptionally expandable hood or sheath attached to an imaging and/ordiagnostic catheter.

FIG. 1C shows an end view of a deployed imaging apparatus.

FIGS. 1D to 1F show the apparatus of FIGS. 1A to 1C with an additionallumen, e.g., for passage of a guidewire therethrough.

FIGS. 2A and 2B show one example of a deployed tissue imager positionedagainst or adjacent to the tissue to be imaged and a flow of fluid, suchas saline, displacing blood from within the expandable hood.

FIG. 3A shows an articulatable imaging assembly which may be manipulatedvia push-pull wires or by computer control.

FIGS. 3B and 3C show steerable instruments, respectively, where anarticulatable delivery catheter may be steered within the imaging hoodor a distal portion of the deployment catheter itself may be steered.

FIGS. 4A to 4C show side and cross-sectional end views, respectively, ofanother variation having an off-axis imaging capability.

FIG. 5 shows an illustrative view of an example of a tissue imageradvanced intravascularly within a heart for imaging tissue regionswithin an atrial chamber.

FIGS. 6A to 6C illustrate deployment catheters having one or moreoptional inflatable balloons or anchors for stabilizing the deviceduring a procedure.

FIGS. 7A and 7B illustrate a variation of an anchoring mechanism such asa helical tissue piercing device for temporarily stabilizing the imaginghood relative to a tissue surface.

FIG. 7C shows another variation for anchoring the imaging hood havingone or more tubular support members integrated with the imaging hood;each support members may define a lumen therethrough for advancing ahelical tissue anchor within.

FIG. 8A shows an illustrative example of one variation of how a tissueimager may be utilized with an imaging device.

FIG. 8B shows a further illustration of a hand-held variation of thefluid delivery and tissue manipulation system.

FIGS. 9A to 9C illustrate an example of capturing several images of thetissue at multiple regions.

FIGS. 10A and 10B show charts illustrating how fluid pressure within theimaging hood may be coordinated with the surrounding blood pressure; thefluid pressure in the imaging hood may be coordinated with the bloodpressure or it may be regulated based upon pressure feedback from theblood.

FIGS. 11A and 11B show side views of a deployment catheter and imaginghood directed proximate or adjacent to a tissue opening to be closed.

FIGS. 12A to 12G illustrate a reconfigurable needle which may bedeployed through a cannula, while under direct visualization, throughone or more layers of tissue surrounding the tissue opening anddeployment of tissue anchors to approximate and secure the opening.

FIGS. 13A to 13E illustrate another variation for closing a tissueopening utilizing a retaining wire having a reconfigurable portionpassed through the tissue.

FIGS. 14A to 14C illustrate yet another variation where a piercingneedle may be passed through the tissue opening and a retaining wiredeployed through the needle for approximating the tissue into a closedconfiguration.

FIGS. 15A to 15E illustrate yet another variation utilizing tissueanchors which may be deployed through a piercing needle to approximateand secure a tissue opening while under direct visualization.

FIGS. 16A and 16B show a variation where a closure mechanism or patchmay be releasably coupled about a circumference of the hood and releasedfor securement over a tissue opening.

FIG. 16C shows a top view of the closure mechanism of FIGS. 16A and 16B.

FIG. 17 shows a perspective view of another variation where a supportring having a patch may have a plurality of barbed projections around acircumference of the ring.

FIGS. 18A and 18B show another variation where the support ring may befabricated from an electrically non-conductive material with a pluralityof electrically conductive reconfigurable projections.

FIGS. 19A and 19B show yet another variation where a support ring may bedelivered in a low-profile configuration attached via a releasablemember through a cannula and expanded for placement over a tissueopening.

FIG. 20 shows a top view of an expanded patch.

FIGS. 21A to 21D show variations of various securement mechanisms forsecuring the patch against a tissue region.

FIG. 22 shows a partial cross-sectional view of a patch deployed againstthe atrial septum over an opening and secured via a plurality of helicalscrews.

FIG. 23 shows a partial cross-sectional view of a heart with anothervariation of a patch device which utilizes support ring, patch materialand a securement member which is reconfigurable from a low-profileconfiguration into an expanded configuration.

FIG. 24A illustrates a perspective view of a variation of the closuredevice of FIG. 23 having one or more projecting barbs extending from thepatch.

FIG. 24B illustrates another variation of the patch without a securementmember.

FIG. 25 illustrates an illustrative view of a laparoscopic variationutilizing a rigid shaft.

DETAILED DESCRIPTION OF THE INVENTION

A tissue-imaging and manipulation apparatus described below is able toprovide real-time images in vivo of tissue regions within a body lumensuch as a heart, which is filled with blood flowing dynamicallytherethrough and is also able to provide intravascular tools andinstruments for performing various procedures upon the imaged tissueregions. Such an apparatus may be utilized for many procedures, e.g.,facilitating trans-septal access to the left atrium, cannulating thecoronary sinus, diagnosis of valve regurgitation/stenosis,valvuloplasty, atrial appendage closure, arrhythmogenic focus ablation,among other procedures.

One variation of a tissue access and imaging apparatus is shown in thedetail perspective views of FIGS. 1A to 1C. As shown in FIG. 1A, tissueimaging and manipulation assembly 10 may be delivered intravascularlythrough the patient's body in a low-profile configuration via a deliverycatheter or sheath 14. In the case of treating tissue, such as themitral valve located at the outflow tract of the left atrium of theheart, it is generally desirable to enter or access the left atriumwhile minimizing trauma to the patient. To non-operatively effect suchaccess, one conventional approach involves puncturing the intra-atrialseptum from the right atrial chamber to the left atrial chamber in aprocedure commonly called a trans-septal procedure or septostomy. Forprocedures such as percutaneous valve repair and replacement,trans-septal access to the left atrial chamber of the heart may allowfor larger devices to be introduced into the venous system than cangenerally be introduced percutaneously into the arterial system.

When the imaging and manipulation assembly 10 is ready to be utilizedfor imaging tissue, imaging hood 12 may be advanced relative to catheter14 and deployed from a distal opening of catheter 14, as shown by thearrow. Upon deployment, imaging hood 12 may be unconstrained to expandor open into a deployed imaging configuration, as shown in FIG. 1B.Imaging hood 12 may be fabricated from a variety of pliable orconformable biocompatible material including but not limited to, e.g.,polymeric, plastic, or woven materials. One example of a woven materialis Kevlar® (E.I. du Pont de Nemours, Wilmington, Del.), which is anaramid and which can be made into thin, e.g., less than 0.001 in.,materials which maintain enough integrity for such applicationsdescribed herein. Moreover, the imaging hood 12 may be fabricated from atranslucent or opaque material and in a variety of different colors tooptimize or attenuate any reflected lighting from surrounding fluids orstructures, i.e., anatomical or mechanical structures or instruments. Ineither case, imaging hood 12 may be fabricated into a uniform structureor a scaffold-supported structure, in which case a scaffold made of ashape memory alloy, such as Nitinol, or a spring steel, or plastic,etc., may be fabricated and covered with the polymeric, plastic, orwoven material.

Imaging hood 12 may be attached at interface 24 to a deployment catheter16 which may be translated independently of deployment catheter orsheath 14. Attachment of interface 24 may be accomplished through anynumber of conventional methods. Deployment catheter 16 may define afluid delivery lumen 18 as well as an imaging lumen 20 within which anoptical imaging fiber or assembly may be disposed for imaging tissue.When deployed, imaging hood 12 may expand into any number of shapes,e.g., cylindrical, conical as shown, semi-spherical, etc., provided thatan open area or field 26 is defined by imaging hood 12. The open area 26is the area within which the tissue region of interest may be imaged.Imaging hood 12 may also define an atraumatic contact lip or edge 22 forplacement or abutment against the tissue region of interest. Moreover,the diameter of imaging hood 12 at its maximum fully deployed diameter,e.g., at contact lip or edge 22, is typically greater relative to adiameter of the deployment catheter 16 (although a diameter of contactlip or edge 22 may be made to have a smaller or equal diameter ofdeployment catheter 16). For instance, the contact edge diameter mayrange anywhere from 1 to 5 times (or even greater, as practicable) adiameter of deployment catheter 16. FIG. 1C shows an end view of theimaging hood 12 in its deployed configuration. Also shown are thecontact lip or edge 22 and fluid delivery lumen 18 and imaging lumen 20.

The imaging and manipulation assembly 10 may additionally define aguidewire lumen therethrough, e.g., a concentric or eccentric lumen, asshown in the side and end views, respectively, of FIGS. 1D to 1F. Thedeployment catheter 16 may define guidewire lumen 19 for facilitatingthe passage of the system over or along a guidewire 17, which may beadvanced intravascularly within a body lumen. The deployment catheter 16may then be advanced over the guidewire 17, as generally known in theart.

In operation, after imaging hood 12 has been deployed, as in FIG. 1B,and desirably positioned against the tissue region to be imaged alongcontact edge 22, the displacing fluid may be pumped at positive pressurethrough fluid delivery lumen 18 until the fluid fills open area 26completely and displaces any fluid 28 from within open area 26. Thedisplacing fluid flow may be laminarized to improve its clearing effectand to help prevent blood from re-entering the imaging hood 12.Alternatively, fluid flow may be started before the deployment takesplace. The displacing fluid, also described herein as imaging fluid, maycomprise any biocompatible fluid, e.g., saline, water, plasma, etc.,which is sufficiently transparent to allow for relatively undistortedvisualization through the fluid. Alternatively or additionally, anynumber of therapeutic drugs may be suspended within the fluid or maycomprise the fluid itself which is pumped into open area 26 and which issubsequently passed into and through the heart and the patient body.

As seen in the example of FIGS. 2A and 2B, deployment catheter 16 may bemanipulated to position deployed imaging hood 12 against or near theunderlying tissue region of interest to be imaged, in this example aportion of annulus A of mitral valve MV within the left atrial chamber.As the surrounding blood 30 flows around imaging hood 12 and within openarea 26 defined within imaging hood 12, as seen in FIG. 2A, theunderlying annulus A is obstructed by the opaque blood 30 and isdifficult to view through the imaging lumen 20. The translucent fluid28, such as saline, may then be pumped through fluid delivery lumen 18,intermittently or continuously, until the blood 30 is at leastpartially, and preferably completely, displaced from within open area 26by fluid 28, as shown in FIG. 2B.

Although contact edge 22 need not directly contact the underlyingtissue, it is at least preferably brought into close proximity to thetissue such that the flow of clear fluid 28 from open area 26 may bemaintained to inhibit significant backflow of blood 30 back into openarea 26. Contact edge 22 may also be made of a soft elastomeric materialsuch as certain soft grades of silicone or polyurethane, as typicallyknown, to help contact edge 22 conform to an uneven or rough underlyinganatomical tissue surface. Once the blood 30 has been displaced fromimaging hood 12, an image may then be viewed of the underlying tissuethrough the clear fluid 30. This image may then be recorded or availablefor real-time viewing for performing a therapeutic procedure. Thepositive flow of fluid 28 may be maintained continuously to provide forclear viewing of the underlying tissue. Alternatively, the fluid 28 maybe pumped temporarily or sporadically only until a clear view of thetissue is available to be imaged and recorded, at which point the fluidflow 28 may cease and blood 30 may be allowed to seep or flow back intoimaging hood 12. This process may be repeated a number of times at thesame tissue region or at multiple tissue regions.

In desirably positioning the assembly at various regions within thepatient body, a number of articulation and manipulation controls may beutilized. For example, as shown in the articulatable imaging assembly 40in FIG. 3A, one or more push-pull wires 42 may be routed throughdeployment catheter 16 for steering the distal end portion of the devicein various directions 46 to desirably position the imaging hood 12adjacent to a region of tissue to be visualized. Depending upon thepositioning and the number of push-pull wires 42 utilized, deploymentcatheter 16 and imaging hood 12 may be articulated into any number ofconfigurations 44. The push-pull wire or wires 42 may be articulated viatheir proximal ends from outside the patient body manually utilizing oneor more controls. Alternatively, deployment catheter 16 may bearticulated by computer control, as further described below.

Additionally or alternatively, an articulatable delivery catheter 48,which may be articulated via one or more push-pull wires and having animaging lumen and one or more working lumens, may be delivered throughthe deployment catheter 16 and into imaging hood 12. With a distalportion of articulatable delivery catheter 48 within imaging hood 12,the clear displacing fluid may be pumped through delivery catheter 48 ordeployment catheter 16 to clear the field within imaging hood 12. Asshown in FIG. 3B, the articulatable delivery catheter 48 may bearticulated within the imaging hood to obtain a better image of tissueadjacent to the imaging hood 12. Moreover, articulatable deliverycatheter 48 may be articulated to direct an instrument or tool passedthrough the catheter 48, as described in detail below, to specific areasof tissue imaged through imaging hood 12 without having to repositiondeployment catheter 16 and re-clear the imaging field within hood 12.

Alternatively, rather than passing an articulatable delivery catheter 48through the deployment catheter 16, a distal portion of the deploymentcatheter 16 itself may comprise a distal end 49 which is articulatablewithin imaging hood 12, as shown in FIG. 3C. Directed imaging,instrument delivery, etc., may be accomplished directly through one ormore lumens within deployment catheter 16 to specific regions of theunderlying tissue imaged within imaging hood 12.

Visualization within the imaging hood 12 may be accomplished through animaging lumen 20 defined through deployment catheter 16, as describedabove. In such a configuration, visualization is available in astraight-line manner, i.e., images are generated from the field distallyalong a longitudinal axis defined by the deployment catheter 16.Alternatively or additionally, an articulatable imaging assembly havinga pivotable support member 50 may be connected to, mounted to, orotherwise passed through deployment catheter 16 to provide forvisualization off-axis relative to the longitudinal axis defined bydeployment catheter 16, as shown in FIG. 4A. Support member 50 may havean imaging element 52, e.g., a CCD or CMOS imager or optical fiber,attached at its distal end with its proximal end connected to deploymentcatheter 16 via a pivoting connection 54.

If one or more optical fibers are utilized for imaging, the opticalfibers 58 may be passed through deployment catheter 16, as shown in thecross-section of FIG. 4B, and routed through the support member 50. Theuse of optical fibers 58 may provide for increased diameter sizes of theone or several lumens 56 through deployment catheter 16 for the passageof diagnostic and/or therapeutic tools therethrough. Alternatively,electronic chips, such as a charge coupled device (CCD) or a CMOSimager, which are typically known, may be utilized in place of theoptical fibers 58, in which case the electronic imager may be positionedin the distal portion of the deployment catheter 16 with electric wiresbeing routed proximally through the deployment catheter 16.Alternatively, the electronic imagers may be wirelessly coupled to areceiver for the wireless transmission of images. Additional opticalfibers or light emitting diodes (LEDs) can be used to provide lightingfor the image or operative theater, as described below in furtherdetail. Support member 50 may be pivoted via connection 54 such that themember 50 can be positioned in a low-profile configuration withinchannel or groove 60 defined in a distal portion of catheter 16, asshown in the cross-section of FIG. 4C. During intravascular delivery ofdeployment catheter 16 through the patient body, support member 50 canbe positioned within channel or groove 60 with imaging hood 12 also inits low-profile configuration. During visualization, imaging hood 12 maybe expanded into its deployed configuration and support member 50 may bedeployed into its off-axis configuration for imaging the tissue adjacentto hood 12, as in FIG. 4A. Other configurations for support member 50for off-axis visualization may be utilized, as desired.

FIG. 5 shows an illustrative cross-sectional view of a heart H havingtissue regions of interest being viewed via an imaging assembly 10. Inthis example, delivery catheter assembly 70 may be introducedpercutaneously into the patient's vasculature and advanced through thesuperior vena cava SVC and into the right atrium RA. The deliverycatheter or sheath 72 may be articulated through the atrial septum ASand into the left atrium LA for viewing or treating the tissue, e.g.,the annulus A, surrounding the mitral valve MV. As shown, deploymentcatheter 16 and imaging hood 12 may be advanced out of delivery catheter72 and brought into contact or in proximity to the tissue region ofinterest. In other examples, delivery catheter assembly 70 may beadvanced through the inferior vena cava IVC, if so desired. Moreover,other regions of the heart H, e.g., the right ventricle RV or leftventricle LV, may also be accessed and imaged or treated by imagingassembly 10.

In accessing regions of the heart H or other parts of the body, thedelivery catheter or sheath 14 may comprise a conventionalintra-vascular catheter or an endoluminal delivery device.Alternatively, robotically-controlled delivery catheters may also beoptionally utilized with the imaging assembly described herein, in whichcase a computer-controller 74 may be used to control the articulationand positioning of the delivery catheter 14. An example of arobotically-controlled delivery catheter which may be utilized isdescribed in further detail in US Pat. Pub. 2002/0087169 A1 to Brock etal. entitled “Flexible Instrument”, which is incorporated herein byreference in its entirety. Other robotically-controlled deliverycatheters manufactured by Hansen Medical, Inc. (Mountain View, Calif.)may also be utilized with the delivery catheter 14.

To facilitate stabilization of the deployment catheter 16 during aprocedure, one or more inflatable balloons or anchors 76 may bepositioned along the length of catheter 16, as shown in FIG. 6A. Forexample, when utilizing a trans-septal approach across the atrial septumAS into the left atrium LA, the inflatable balloons 76 may be inflatedfrom a low-profile into their expanded configuration to temporarilyanchor or stabilize the catheter 16 position relative to the heart H.FIG. 6B shows a first balloon 78 inflated while FIG. 6C also shows asecond balloon 80 inflated proximal to the first balloon 78. In such aconfiguration, the septal wall AS may be wedged or sandwiched betweenthe balloons 78, 80 to temporarily stabilize the catheter 16 and imaginghood 12. A single balloon 78 or both balloons 78, 80 may be used. Otheralternatives may utilize expandable mesh members, malecots, or any othertemporary expandable structure. After a procedure has been accomplished,the balloon assembly 76 may be deflated or re-configured into alow-profile for removal of the deployment catheter 16.

To further stabilize a position of the imaging hood 12 relative to atissue surface to be imaged, various anchoring mechanisms may beoptionally employed for temporarily holding the imaging hood 12 againstthe tissue. Such anchoring mechanisms may be particularly useful forimaging tissue which is subject to movement, e.g., when imaging tissuewithin the chambers of a beating heart. A tool delivery catheter 82having at least one instrument lumen and an optional visualization lumenmay be delivered through deployment catheter 16 and into an expandedimaging hood 12. As the imaging hood 12 is brought into contact againsta tissue surface T to be examined, an anchoring mechanisms such as ahelical tissue piercing device 84 may be passed through the tooldelivery catheter 82, as shown in FIG. 7A, and into imaging hood 12.

The helical tissue engaging device 84 may be torqued from its proximalend outside the patient body to temporarily anchor itself into theunderlying tissue surface T. Once embedded within the tissue T, thehelical tissue engaging device 84 may be pulled proximally relative todeployment catheter 16 while the deployment catheter 16 and imaging hood12 are pushed distally, as indicated by the arrows in FIG. 7B, to gentlyforce the contact edge or lip 22 of imaging hood against the tissue T.The positioning of the tissue engaging device 84 may be lockedtemporarily relative to the deployment catheter 16 to ensure securepositioning of the imaging hood 12 during a diagnostic or therapeuticprocedure within the imaging hood 12. After a procedure, tissue engagingdevice 84 may be disengaged from the tissue by torquing its proximal endin the opposite direction to remove the anchor form the tissue T and thedeployment catheter 16 may be repositioned to another region of tissuewhere the anchoring process may be repeated or removed from the patientbody. The tissue engaging device 84 may also be constructed from otherknown tissue engaging devices such as vacuum-assisted engagement orgrasper-assisted engagement tools, among others.

Although a helical anchor 84 is shown, this is intended to beillustrative and other types of temporary anchors may be utilized, e.g.,hooked or barbed anchors, graspers, etc. Moreover, the tool deliverycatheter 82 may be omitted entirely and the anchoring device may bedelivered directly through a lumen defined through the deploymentcatheter 16.

In another variation where the tool delivery catheter 82 may be omittedentirely to temporarily anchor imaging hood 12, FIG. 7C shows an imaginghood 12 having one or more tubular support members 86, e.g., foursupport members 86 as shown, integrated with the imaging hood 12. Thetubular support members 86 may define lumens therethrough each havinghelical tissue engaging devices 88 positioned within. When an expandedimaging hood 12 is to be temporarily anchored to the tissue, the helicaltissue engaging devices 88 may be urged distally to extend from imaginghood 12 and each may be torqued from its proximal end to engage theunderlying tissue T. Each of the helical tissue engaging devices 88 maybe advanced through the length of deployment catheter 16 or they may bepositioned within tubular support members 86 during the delivery anddeployment of imaging hood 12. Once the procedure within imaging hood 12is finished, each of the tissue engaging devices 88 may be disengagedfrom the tissue and the imaging hood 12 may be repositioned to anotherregion of tissue or removed from the patient body.

An illustrative example is shown in FIG. 8A of a tissue imaging assemblyconnected to a fluid delivery system 90 and to an optional processor 98and image recorder and/or viewer 100. The fluid delivery system 90 maygenerally comprise a pump 92 and an optional valve 94 for controllingthe flow rate of the fluid into the system. A fluid reservoir 96,fluidly connected to pump 92, may hold the fluid to be pumped throughimaging hood 12. An optional central processing unit or processor 98 maybe in electrical communication with fluid delivery system 90 forcontrolling flow parameters such as the flow rate and/or velocity of thepumped fluid. The processor 98 may also be in electrical communicationwith an image recorder and/or viewer 100 for directly viewing the imagesof tissue received from within imaging hood 12. Imager recorder and/orviewer 100 may also be used not only to record the image but also thelocation of the viewed tissue region, if so desired.

Optionally, processor 98 may also be utilized to coordinate the fluidflow and the image capture. For instance, processor 98 may be programmedto provide for fluid flow from reservoir 96 until the tissue area hasbeen displaced of blood to obtain a clear image. Once the image has beendetermined to be sufficiently clear, either visually by a practitioneror by computer, an image of the tissue may be captured automatically byrecorder 100 and pump 92 may be automatically stopped or slowed byprocessor 98 to cease the fluid flow into the patient. Other variationsfor fluid delivery and image capture are, of course, possible and theaforementioned configuration is intended only to be illustrative and notlimiting.

FIG. 8B shows a further illustration of a hand-held variation of thefluid delivery and tissue manipulation system 110. In this variation,system 110 may have a housing or handle assembly 112 which can be heldor manipulated by the physician from outside the patient body. The fluidreservoir 114, shown in this variation as a syringe, can be fluidlycoupled to the handle assembly 112 and actuated via a pumping mechanism116, e.g., lead screw. Fluid reservoir 114 may be a simple reservoirseparated from the handle assembly 112 and fluidly coupled to handleassembly 112 via one or more tubes. The fluid flow rate and othermechanisms may be metered by the electronic controller 118.

Deployment of imaging hood 12 may be actuated by a hood deploymentswitch 120 located on the handle assembly 112 while dispensation of thefluid from reservoir 114 may be actuated by a fluid deployment switch122, which can be electrically coupled to the controller 118. Controller118 may also be electrically coupled to a wired or wireless antenna 124optionally integrated with the handle assembly 112, as shown in thefigure. The wireless antenna 124 can be used to wirelessly transmitimages captured from the imaging hood 12 to a receiver, e.g., viaBluetooth® wireless technology (Bluetooth SIG, Inc., Bellevue, Wash.),RF, etc., for viewing on a monitor 128 or for recording for laterviewing.

Articulation control of the deployment catheter 16, or a deliverycatheter or sheath 14 through which the deployment catheter 16 may bedelivered, may be accomplished by computer control, as described above,in which case an additional controller may be utilized with handleassembly 112. In the case of manual articulation, handle assembly 112may incorporate one or more articulation controls 126 for manualmanipulation of the position of deployment catheter 16. Handle assembly112 may also define one or more instrument ports 130 through which anumber of intravascular tools may be passed for tissue manipulation andtreatment within imaging hood 12, as described further below.Furthermore, in certain procedures, fluid or debris may be sucked intoimaging hood 12 for evacuation from the patient body by optionallyfluidly coupling a suction pump 132 to handle assembly 112 or directlyto deployment catheter 16.

As described above, fluid may be pumped continuously into imaging hood12 to provide for clear viewing of the underlying tissue. Alternatively,fluid may be pumped temporarily or sporadically only until a clear viewof the tissue is available to be imaged and recorded, at which point thefluid flow may cease and the blood may be allowed to seep or flow backinto imaging hood 12. FIGS. 9A to 9C illustrate an example of capturingseveral images of the tissue at multiple regions. Deployment catheter 16may be desirably positioned and imaging hood 12 deployed and broughtinto position against a region of tissue to be imaged, in this examplethe tissue surrounding a mitral valve MV within the left atrium of apatient's heart. The imaging hood 12 may be optionally anchored to thetissue, as described above, and then cleared by pumping the imagingfluid into the hood 12. Once sufficiently clear, the tissue may bevisualized and the image captured by control electronics 118. The firstcaptured image 140 may be stored and/or transmitted wirelessly 124 to amonitor 128 for viewing by the physician, as shown in FIG. 9A.

The deployment catheter 16 may be then repositioned to an adjacentportion of mitral valve MV, as shown in FIG. 9B, where the process maybe repeated to capture a second image 142 for viewing and/or recording.The deployment catheter 16 may again be repositioned to another regionof tissue, as shown in FIG. 9C, where a third image 144 may be capturedfor viewing and/or recording. This procedure may be repeated as manytimes as necessary for capturing a comprehensive image of the tissuesurrounding mitral valve MV, or any other tissue region. When thedeployment catheter 16 and imaging hood 12 is repositioned from tissueregion to tissue region, the pump may be stopped during positioning andblood or surrounding fluid may be allowed to enter within imaging hood12 until the tissue is to be imaged, where the imaging hood 12 may becleared, as above.

As mentioned above, when the imaging hood 12 is cleared by pumping theimaging fluid within for clearing the blood or other bodily fluid, thefluid may be pumped continuously to maintain the imaging fluid withinthe hood 12 at a positive pressure or it may be pumped under computercontrol for slowing or stopping the fluid flow into the hood 12 upondetection of various parameters or until a clear image of the underlyingtissue is obtained. The control electronics 118 may also be programmedto coordinate the fluid flow into the imaging hood 12 with variousphysical parameters to maintain a clear image within imaging hood 12.

One example is shown in FIG. 10A which shows a chart 150 illustratinghow fluid pressure within the imaging hood 12 may be coordinated withthe surrounding blood pressure. Chart 150 shows the cyclical bloodpressure 156 alternating between diastolic pressure 152 and systolicpressure 154 over time T due to the beating motion of the patient heart.The fluid pressure of the imaging fluid, indicated by plot 160, withinimaging hood 12 may be automatically timed to correspond to the bloodpressure changes 160 such that an increased pressure is maintainedwithin imaging hood 12 which is consistently above the blood pressure156 by a slight increase ΔP, as illustrated by the pressure differenceat the peak systolic pressure 158. This pressure difference, ΔP, may bemaintained within imaging hood 12 over the pressure variance of thesurrounding blood pressure to maintain a positive imaging fluid pressurewithin imaging hood 12 to maintain a clear view of the underlyingtissue. One benefit of maintaining a constant ΔP is a constant flow andmaintenance of a clear field.

FIG. 10B shows a chart 162 illustrating another variation formaintaining a clear view of the underlying tissue where one or moresensors within the imaging hood 12, as described in further detailbelow, may be configured to sense pressure changes within the imaginghood 12 and to correspondingly increase the imaging fluid pressurewithin imaging hood 12. This may result in a time delay, ΔT, asillustrated by the shifted fluid pressure 160 relative to the cyclingblood pressure 156, although the time delay ΔT may be negligible inmaintaining the clear image of the underlying tissue. Predictivesoftware algorithms can also be used to substantially eliminate thistime delay by predicting when the next pressure wave peak will arriveand by increasing the pressure ahead of the pressure wave's arrival byan amount of time equal to the aforementioned time delay to essentiallycancel the time delay out.

The variations in fluid pressure within imaging hood 12 may beaccomplished in part due to the nature of imaging hood 12. An inflatableballoon, which is conventionally utilized for imaging tissue, may beaffected by the surrounding blood pressure changes. On the other hand,an imaging hood 12 retains a constant volume therewithin and isstructurally unaffected by the surrounding blood pressure changes, thusallowing for pressure increases therewithin. The material that hood 12is made from may also contribute to the manner in which the pressure ismodulated within this hood 12. A stiffer hood material, such as highdurometer polyurethane or Nylon, may facilitate the maintaining of anopen hood when deployed. On the other hand, a relatively lower durometeror softer material, such as a low durometer PVC or polyurethane, maycollapse from the surrounding fluid pressure and may not adequatelymaintain a deployed or expanded hood.

With the imaging hood 12, any number of intravascular procedures may beperformed especially while under direct visualization, including theclosure or apposition of tissue wounds or openings. Turning now to theside view of FIG. 11A, deployment catheter 16 and imaging hood 12 may bedirected, in one example of use, to intravascularly closing a coronarydefect such as an atrial septal defect (ASD) or a patent foramen ovale(PFO) 170. The tissue defect, in this example PFO 170, is formed alongthe atrial septum AS between the septum primum SP and septum secundum SSand defines an opening 172 which allows blood to be shunted between theleft and right atrial chambers. With deployment catheter 16 advancedintravascularly into the left or right atrial chamber, hood 12 may bearticulated or directed via catheter 16 into contact with a portion ofthe atrial septum AS adjacent or proximate to the opening 172.

Once desirably positioned, hood 12 may be optionally purged of blood orfluids to allow for direct visualization of the underlying tissuethrough hood 12 and cannula 174 may be advanced through one of theworking lumens into contact against the tissue, as shown in FIG. 11B. Apiercing needle 176 having a needle lumen 178 may be advanced distallythrough cannula 174 until the needle tip pierces through the atrialseptum AS, as shown in FIG. 12A. (Hood 12 is omitted for the sake ofclarity.) Needle 176 may be formed of a shape memory alloy or otherpre-formed metal, as described above, such that the needle 176 defines aportion 180 proximal to the needle tip which is biased to curve or iscurvable upon being unconstrained from the cannula 174, as illustratedin FIG. 12B. As the needle 176 is further advanced, curved portion 180may be free to curve into an arcuate or retro-flexed configuration suchthat the piercing tip of the needle may be pulled proximally to pierceback through the tissue, e.g., through the septum secundum SS and septumprimum SP, until the tip reappears on the same side of the chamber ascannula 174, as illustrated in FIG. 12C. Once needle lumen 178 hascleared the tissue, a first anchor 182 connected via a length of suture186 may be deployed from needle 176. With first anchor 182 deployed,needle 176 may be withdrawn proximally back through the tissue layersleaving first anchor 182 to rest against the tissue surface whileremaining coupled or connected to suture 186, as illustrated in FIG.12D.

Needle 176 may be further withdrawn back into cannula 174 such thatneedle 176 is pulled back through the tissue, where a second anchor 184coupled or connected to suture 186 may be ejected or urged from needlelumen 178, as illustrated in FIG. 12E. As needle 176 is pulledproximally back into cannula 174, it may be straightened back into itsdelivery configuration. With both anchors 182, 184 ejected from needle176 and connected to one another via suture 186 routed through thetissue layers forming opening 172 of PFO 170, the anchors 182, 184 maybe urged towards one another to cinch the PFO 170 closed and a lockingmechanism 188 may be passed along the suture 186 proximal to secondanchor 188 to ensure that suture 186 remains tensioned between anchors182, 184, as shown in FIG. 12F. With PFO 170 cinched shut, suture 186proximal to locking mechanism 188 may be cut or otherwise released toleave anchors 182, 184 and suture 186 behind, as illustrated in FIG.12G.

Alternative mechanisms for releasing anchors through tissue are shownand described in further detail in U.S. Pat. Pub. No. 2005/0059984 A1 toChanduszko et al. and further examples of locking mechanisms which maybe utilized herein are also described in U.S. Pat. Pub. No. 2003/0018358A1 to Saadat, each of which are incorporated herein by reference in itsentirety.

In another variation for closing a PFO or other tissue opening is shownin FIGS. 13A to 13E. As above, deployment catheter 16 and hood 12 may bearticulated into position over tissue opening 172, where cannula 174 maybe advanced distally within hood 12 into contact against the underlyingtissue, as shown in FIG. 13A. FIG. 13B illustrates a detail view ofcannula 174 against the underlying tissue with the hood omitted for thesake of clarity. A retaining wire 190 having a piercing tip and madefrom a shape memory alloy or other metal, as described above, may beadvanced distally through the cannula lumen until it pierces through thetissue layers SP, SS surrounding opening 172. Once free from theconstraints of cannula 174, the distal portion 192 of retaining wire190, which may be preformed or biased to expand or reconfigure itselfinto an enlarged retaining configuration, may begin to expand, as shownin FIG. 13C.

As retaining wire 190 is further urged distally through the tissue,pre-formed portion 192 may fully reconfigure itself in a shape whichresists being pulled proximally through the tissue, as shown in FIG.13D. With this configuration, retaining wire 190 may be pulledproximally through cannula 174, as indicated by the arrow, toapproximate the tissue layers towards one another and close the opening172 of PFO 170, as shown in FIG. 13E. Once the tissue opening has beenclosed, retaining wire 190 may be detached and secured in place orfurther procedures may be performed upon the tissue to otherwise securethe closed opening, in which case wire 190 may be then withdrawn intocannula 174 and back into its straightened configuration for withdrawalfrom the patient body.

In yet another variation, deployment catheter 16 and hood 12 may bearticulated or otherwise guided into position or proximity to opening172 and piercing needle 200 may be advanced through hood 12 while underdirect visualization through the purged hood 12, as shown in FIG. 14A.Needle 200 may be pierced through the layers SP, SS of the opening 172until piercing tip 202 has cleared the tissue and is within the adjacentchamber. Retaining wire 190 may then be advanced through needle lumen204 until the pre-formed portion 192 has been deployed from lumen 204and expanded, as shown in FIG. 14B. Needle 200 may then be withdrawnproximally through the tissue until piercing tip 202 has cleared thetissue. Retaining wire 190 may then be urged proximally, as indicated bythe arrow, to approximate the tissue surrounding the opening 172 andportion 192 may be left in place or another procedure may be performedupon the tissue to maintain closure of the opening, as above and asshown in FIG. 14C.

In yet another variation, with deployment catheter 16 and hood 12 urgedinto position proximate to opening 172, piercing needle 200 may be urgedthrough the tissue layers until piercing tip 202 has pierced through andcleared the tissue, as described above and as shown in FIG. 15A. Onceneedle 200 is in its desired position, first anchor 182 connected viasuture 186, may be urged through needle lumen 204 and ejected, as shownin FIG. 15B. Needle tip 202 may then be withdrawn proximally through thetissue, as shown in FIG. 15C, where second anchor 184 also coupled viasuture 186 may be ejected from needle lumen 204. Locking mechanism 188may then be ejected and drawn over suture 186 until it bears upon secondanchor 184 and approximates first and second anchors 182, 184 towardsone another thereby closing tissue opening 172 between the layers oftissue, as shown in FIG. 15D. Suture 186 may then be detached to leavethe anchor assembly 182, 184 and locking mechanism 188 in place tomaintain securement of the closure. The entire procedure may beperformed under direct visualization through the hood 12, if so desired,to ensure sufficient anchor deployment and closure of opening 172.

In yet another variation for effecting closure of a tissue opening, FIG.16A shows a variation where closure mechanism or patch 210 may betemporarily affixed or releasably coupled about a circumference or lip218 of hood 12. A non-porous patch material 212, which may befabricated, extruded, woven, etc., from any number of biocompatiblematerials such as polyester, polypropylene, polyethylene, nylon, PTFE,PFE, polyurethane, etc. or blends thereof, may be supported upon supportring 216, which may be coupled to hood 12. Support ring 216 may befabricated from any number of biocompatible materials such as shapememory alloys, as above, which may enable ring 216 to be configuredbetween a low-profile delivery shape which is positionable withindelivery catheter 16 or a sheath and an expanded shape which conforms tothe deployed hood 12.

Support ring 216 may comprise a number of tissue engaging projections214 which are positioned around ring 216 in a distally projectingorientation such that when expanded and urged against tissue, ring 216may be secured to the tissue. As shown in FIG. 16B, ring 216 may be of adiameter which is sufficiently large enough to encircle the periphery ofopening 172 such that patch 212 may completely or at least partiallyencompass opening 172. After catheter 16 urges hood 12 and projections214 into the tissue surrounding opening 172, ring 216 may be detachedfrom hood 12 via a release mechanism to leave ring 216 and patch 212covering opening 172. FIG. 16C illustrates an end view of support ring216 and patch 212 showing one variation where suture 220 may be routedaround the circumference of ring 216 through one or more suture supports222, e.g., eyelets, openings, etc., to secure ring 216 to hood 12. Whenreleased from hood 12, suture 220 may be pulled proximally to releasering 216 for implantation upon the tissue, thereby allowing hood 12 tobe withdrawn from the patient body.

FIG. 17 shows a perspective view of another variation where support ring230 having patch 212 may have a plurality of barbed projections 232around a circumference of ring 230 for securing the device to the tissuesurrounding the tissue opening. FIGS. 18A and 18B show another variationwhere support ring 236 may be fabricated from an electricallynon-conductive material with a plurality of electrically conductivereconfigurable projections 234 (e.g., electro-active polymer,heat-activatable shape memory alloys, etc.) inter-connected via aconductive wire 238. In such a variation, electrical energy provided viapower supply 240 through wire 238 may energize projections 234 such thatthey maintain a straightened configuration during deployment into thetissue. Once suitably positioned within the tissue, electrical energymay be switched off 242 such that projections are automaticallyreconfigured into a curved configuration 234′ which inhibits ring 236from being pulled or dislodged from the tissue, as shown in FIG. 18B.

In yet another variation utilizing a patch, support ring 216 havingpatch material 212 may be delivered in a low-profile configurationattached via releasable member 250 through cannula 174, as shown in FIG.19A. Once patch 212 is proximate to the opening to be closed, ring 216may be deployed or expanded, as shown in FIG. 19B, and placed intoposition over the opening via cannula 174. Support ring 216, shown inFIG. 20, may be secured to the underlying tissue via any number ofsecurement devices which may be passed through the patch 212 and intothe tissue for securement. Some non-limiting examples of securementdevices are illustrated in FIGS. 21A to 21D, which shows a variation inFIG. 21A of a multi-barbed securement member which may be driven via anynumber of instruments through patch 212 and into the tissue. FIG. 21Bshows another variation of a single-barbed securement member while FIG.21C shows a securement member configured as a staple 256 and FIG. 21Dshows yet another variation of a securement member configured as ahelical screw 258. FIG. 22 shows an example in the partialcross-sectional view of patch 212 deployed against the atrial septum ASover the tissue opening with a plurality of helical screws 258 driventhrough the patch 212 and into the underlying tissue.

FIG. 23 shows a partial cross-sectional view of a heart with anothervariation of a patch device which utilizes support ring 216, patchmaterial 212 and a securement member 260 which is reconfigurable from alow-profile configuration into an expanded configuration which inhibitspulling through the tissue. In this variation, securement member 260 maybe fabricated from a shape memory material, as above, which extends froma center of patch 212. When deployed, member 260 may be passed in alow-profile configuration through the tissue opening and then releasedto allow member 260 to reconfigure into its expanded configuration. Onceexpanded, it may urge the patch 212 disposed on the opposite side of thetissue opening towards the tissue to ensure a secure closure of theopening, much like a spring.

FIG. 24A illustrates a perspective view of a variation of the closuredevice of FIG. 23. As shown, member 260 may be seen as extending frompatch 212 although in this variation, one or more projecting barbs 262may extend from patch 212 towards member 260 to additionally secure thepatch 212 to the tissue. FIG. 24B illustrates another variation of patch212 having the one or more barbs 262 projecting therefrom but withoutmember 260.

Additional variations of patch devices and closure systems are shown anddescribed in further detail in U.S. patent application Ser. No.11/259,498, which has been incorporated by reference above.

Although the devices and methods are described above as utilizingintravascular delivery and deployment, any of the above may bealternatively utilized via a laparoscopic approach. For instance, asshown in the illustrative view of FIG. 25, any of the methods anddevices may lend themselves to use of a laparoscopic variation 270utilizing a rigid shaft 272 and handle 274, e.g., for use on an externalsurface of the heart H, or via an intra-cardiac approach.

The applications of the disclosed invention discussed above are notlimited to certain treatments or regions of the body, but may includeany number of other treatments and areas of the body. Modification ofthe above-described methods and devices for carrying out the invention,and variations of aspects of the invention that are obvious to those ofskill in the arts are intended to be within the scope of thisdisclosure. Moreover, various combinations of aspects between examplesare also contemplated and are considered to be within the scope of thisdisclosure as well.

1. A tissue closure system, comprising: a deployment catheter definingat least one lumen therethrough; a hood comprising a non-inflatablemembrane forming a fluid barrier projecting distally from the deploymentcatheter and adapted to self-expand into an expanded deployedconfiguration defining an open area therein, wherein the open area is influid communication with the at least one lumen and with an environmentexternal to the hood through an opening defined by the hood; avisualization element disposed within or adjacent to the open area ofthe hood for visualizing tissue adjacent to the open area; and a tissueapproximation assembly deployable from within the hood and configured tosecure a tissue opening.
 2. The system of claim 1 further comprising adelivery catheter through which the deployment catheter is deliverable.3. The system of claim 1 wherein the deployment catheter is steerable.4. The system of claim 3 wherein the deployment catheter is steered viaat least one push-pull wire.
 5. The system of claim 3 wherein thedeployment catheter is steered via computer control.
 6. The system ofclaim 1 wherein the hood is comprised of a compliant material.
 7. Thesystem of claim 1 wherein the hood defines a contact edge for placementagainst a tissue surface.
 8. The system of claim 1 wherein the hood isadapted to be reconfigured from a low-profile delivery configuration toan expanded deployed configuration.
 9. The system of claim 8 wherein thehood comprises a frame of superelastic or shape memory alloy.
 10. Thesystem of claim 1 wherein the visualization element comprises at leastone optical fiber, CCD imagers, or CMOS imagers.
 11. The system of claim1 wherein the visualization element is disposed within a distal end ofthe deployment catheter.
 12. The system of claim 1 wherein thevisualization element is articulatable off-axis relative to alongitudinal axis of the deployment catheter.
 13. The system of claim 1further comprising a pump for urging fluid into the hood.
 14. The systemof claim 1 further comprising a cannula or needle defining a lumenthrough which the tissue approximation assembly is disposable.
 15. Thesystem of claim 14 wherein the needle comprises a reconfigurable portionproximal to a piercing tip.
 16. The system of claim 1 wherein the tissueapproximation assembly comprises a first and a second tissue anchorslidingly coupled to one another via a length of suture.
 17. The systemof claim 1 wherein the tissue approximation assembly comprises aretaining wire having a reconfigurable distal portion.
 18. The system ofclaim 1 wherein the tissue approximation assembly comprises a patchmechanism having a ring with a patch supported thereby.
 19. The systemof claim 18 wherein the ring comprises at least one tissue securingprojection.
 20. The system of claim 18 further comprising a plurality oftissue securement members which are deployable through the patch andinto an underlying tissue region.